During the changing of the guard with the cold air, a wedge of warm air will bring rain to portions of the Ohio Valley.

Where the cold air fails to leave quickly enough, some or all of the precipitation will fall in the form of snow.

At this time the major travel hubs of Chicago and Detroit are most likely to have a light to moderate snowfall from the storm. People hitting the highways late in the week should be prepared for wintry travel, including along Interstate 80 and I-94.

According to AccuWeather Senior Meteorologist John Gresiak, "There is the potential for several hours of heavy snow in the swath from northern Illinois to part of the Lower Peninsula of Michigan."

Meanwhile, all or mostly rain is likely in St. Louis, Cincinnati and Pittsburgh. Motorists venturing along I-70 could still be faced with snow or a mix during part of the storm.

"While the rain will not be excessive in the Ohio Valley, fog could be a significant problem for commuters," Gresiak said.

The weather setup will be complex.

The main storm will track from the southern Rockies and Plains to the Great Lakes region.

The exact track of the storm and how quickly a new storm forms along the Atlantic coast will determine where the boundary between snow, a wintry mix and rain will occur, as well as where the band of heavy snow will develop.

The storm on the Atlantic coast is likely to steal much of the moisture, resulting in light to moderate precipitation over the Midwest.

The scenario of a rapidly strengthening Atlantic coast storm could help to draw cold air back in to part of the Midwest with a change from rain to snow or snow showers.

The change back to a period of snow, if it occurs, would be from west to east across the middle Mississippi and Ohio valleys during Friday night into Saturday.

Farther to the east, the storm is likely to bring all or mostly rain to the I-95 corridor from Washington, D.C., to New York City, and a combination of snow and rain to Boston during Friday night and Saturday.

In the central Appalachians, part of the storm will bring snow and ice.

The heaviest snow from the event is likely in part of central and northern New England on Saturday.

"Arctic air will circulate across the Midwest in the wake of the storm at the end of the week," according to AccuWeather Chief Long-Range Meteorologist Paul Pastelok. "However, rather than the arctic air locking in for an extended stay, back-and-forth bouts of milder Pacific air and cold outbreaks are likely through the end of January."